The present invention relates to a stereo adapter, a pattern projection adapter and an adapter for a light-emitting module.
Various techniques are proposed for improving photographing of a parallax image.
Jpn. Pat. Appln. KOKOKU Publication No. 4-25758 discloses a technique for easily making a left parallax image correspond to a right parallax image by irradiating a specific pattern onto an object and photographing again the subject when sufficient correspondence of the photographed left parallax image and the photographed right parallax image cannot be obtained when parallax images of the object are photographed with two cameras. According to this technique, even if a surface of the object is simple and less pictorial characteristic portions utilized for making the left parallax image correspond to the right parallax image are provided, because a specific pattern is projected onto the surface of the object, the pictorial characteristic portions appear on the surface of the image. As a result, the correspondence between the parallax images can be easily obtained.
Jpn. Pat. Appln. KOKAI Publication No. 9-281614 discloses a stereo adapter which is placed in front of a lens of an ordinary camera and can photograph a parallax image by a mirror dividing a light ray. In accordance with this technique, the parallax image can be easily photographed by using an ordinary camera instead of a camera for photographing a parallax image.
However, in the above-described technique disclosed in Jpn. Pat. Appln. KOKOKU Publication No. 4-25758, two cameras and a pattern projection machine are required and the device becomes large. Thus it is difficult to actually apply this technique to somewhere other than a dedicated studio. Further, it is difficult for the timing for pressing the shutter release button of one camera to be synchronized with the timing for pressing the shutter release button of another camera. Moreover, pattern projection and flash illumination need to be performed at this synchronized timing. Accordingly, high speed synchronization is difficult. A process for determining whether correspondence of parallax images is easily performed is complicated.
In Jpn. Pat. Appln. KOKAI Publication No. 9-281614, since the adapter is disposed in front of the photographing device, when a flash or the like is used, the flash must be emitted at a position which is sufficiently spaced apart from the adapter so as not to form a shadow of the adapter. However, if the position of the flash is spaced apart from the adapter, the optical axis for photographing is largely apart from the direction of flash such that a shadow formed on the object by the flash light becomes large and the shadow becomes an obstruction on the image. In the adapter in particular, when the distance of base line is determined to be sufficiently large to improve a performance for identifying the distance on the basis of the parallax image or when photography is performed with larger angle of view, the size of the adapter must be large. Thus, the above-described problem with respect to the shadow is serious. When the technique disclosed in Jpn. Pat. Appln. KOKOKU Publication No. 4-25758 for projecting a pattern is applied to a camera with the adapter attached thereto, the same phenomena as the case of shadow formed by the flash light occurs at a time of projecting the pattern, and an area with the pattern not being projected is formed at the object.